# Copyright (C) 2018-2019 Chris Lalancette # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; # version 2.1 of the License. # This library is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # Lesser General Public License for more details. # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, write to the Free Software # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA ''' PyCdlib Inode class. ''' from __future__ import absolute_import from pycdlib import pycdlibexception # For mypy annotations if False: # pylint: disable=using-constant-test from typing import BinaryIO, List, Optional, Tuple, Union # NOQA pylint: disable=unused-import # NOTE: this import has to be here to avoid circular deps from pycdlib import dr # NOQA pylint: disable=unused-import from pycdlib import eltorito # NOQA pylint: disable=unused-import from pycdlib import udf # NOQA pylint: disable=unused-import class Inode(object): ''' A class that represents an inode, the pointer to a piece of data (not metadata) on an ISO. ''' __slots__ = ('_initialized', 'new_extent_loc', 'orig_extent_loc', 'linked_records', 'data_length', 'manage_fp', 'data_fp', 'original_data_location', 'fp_offset', 'boot_info_table', 'num_udf') DATA_ON_ORIGINAL_ISO = 1 DATA_IN_EXTERNAL_FP = 2 def __init__(self): # type: () -> None self.linked_records = [] # type: List[Tuple[Union[eltorito.EltoritoEntry, udf.UDFFileEntry, dr.DirectoryRecord], bool]] self._initialized = False self.data_length = 0 self.num_udf = 0 self.boot_info_table = None # type: Optional[eltorito.EltoritoBootInfoTable] self.new_extent_loc = -1 def new(self, length, fp, manage_fp, offset): # type: (int, Union[BinaryIO, str], bool, int) -> None ''' Initialize a new Inode. Parameters: None. Returns: Nothing. ''' if self._initialized: raise pycdlibexception.PyCdlibInternalError('Inode is already initialized') self.data_length = length self.data_fp = fp self.manage_fp = manage_fp self.fp_offset = offset self.original_data_location = self.DATA_IN_EXTERNAL_FP self._initialized = True def parse(self, extent, length, fp, log_block_size): # type: (int, int, BinaryIO, int) -> None ''' Parse an existing Inode. This just saves off the extent for later use. Parameters: extent - The original extent that the data lives at. Returns: Nothing. ''' if self._initialized: raise pycdlibexception.PyCdlibInternalError('Inode is already initialized') self.orig_extent_loc = extent self.data_length = length self.data_fp = fp self.manage_fp = False self.fp_offset = extent * log_block_size self.original_data_location = self.DATA_ON_ORIGINAL_ISO self._initialized = True def extent_location(self): # type: () -> int ''' Get the current location of this Inode on the ISO. Parameters: None. Returns: The extent location of this Inode on the ISO. ''' if not self._initialized: raise pycdlibexception.PyCdlibInternalError('Inode is not initialized') if self.new_extent_loc < 0: return self.orig_extent_loc return self.new_extent_loc def set_extent_location(self, extent): # type: (int) -> None ''' Set the current location of this Inode on the ISO. Parameters: extent - The new extent location for this Inode. Returns: Nothing. ''' if not self._initialized: raise pycdlibexception.PyCdlibInternalError('Inode is not initialized') self.new_extent_loc = extent def get_data_length(self): # type: () -> int ''' Get the length of the data pointed to by this Inode. Parameters: None. Returns: The length of the data pointed to by this Inode. ''' if not self._initialized: raise pycdlibexception.PyCdlibInternalError('Inode is not initialized') return self.data_length def add_boot_info_table(self, boot_info_table): # type: (eltorito.EltoritoBootInfoTable) -> None ''' Add a boot info table to this Inode. Parameters: boot_info_table - The Boot Info Table object to add to this Inode. Returns: Nothing. ''' if not self._initialized: raise pycdlibexception.PyCdlibInternalError('Inode is not initialized') self.boot_info_table = boot_info_table def update_fp(self, fp, length): # type: (BinaryIO, int) -> None ''' Update the Inode to use a different file object and length. Parameters: fp - A file object that contains the data for this Inode. length - The length of the data. Returns: Nothing. ''' if not self._initialized: raise pycdlibexception.PyCdlibInternalError('Inode is not initialized') self.original_data_location = self.DATA_IN_EXTERNAL_FP self.data_fp = fp self.data_length = length self.fp_offset = 0 class InodeOpenData(object): ''' A class to be a contextmanager for opening data on a DirectoryRecord object. ''' __slots__ = ('ino', 'logical_block_size', 'data_fp') def __init__(self, ino, logical_block_size): # type: (Inode, int) -> None self.ino = ino self.logical_block_size = logical_block_size def __enter__(self): if self.ino.manage_fp: # In the case that we are managing the FP, the data_fp member # actually contains the filename, not the fp. Use that to # our advantage here. self.data_fp = open(self.ino.data_fp, 'rb') else: self.data_fp = self.ino.data_fp if self.ino.original_data_location == self.ino.DATA_ON_ORIGINAL_ISO: self.data_fp.seek(self.ino.orig_extent_loc * self.logical_block_size) else: self.data_fp.seek(self.ino.fp_offset) return self.data_fp, self.ino.data_length def __exit__(self, *args): if self.ino.manage_fp: self.data_fp.close()